Spraying apparatus



July 29,V l941 M. M. sAvEpoFF 2,250,783

SPRAYING APPARATUS Filed Nov. 29, '1939 2 sheets-smet 1 ATTORNEY July 29, 1941.

M. M. sAyl-:DOFF SPRAYING APARATUS 2 sheets-sheet 2` Filed Nov. 29, 1939 Patented July 29, 1941 UNlTEB Tas Prem orties' v` SPRAYING APPARATUS Morris M. Savecloi, Brooklyn, N. Y. Application November 29, 1939, Serial No. 306,591

.(Cl. Sil-12.2)

2 Claims.

This invention relates generally to spraying apparatus and is more particularly directed to improvements in so-called spray guns, especially of those types which are employed for sprayingmolten metal or metallic alloys, in the treatmentv of metalli-c surfaces for various pur- DoSesr ,Y

While my invention, as will become manifest, is susceptible of a Wide range of application, for the purposes of Vrthis disclosure, I have elected to present it asit may be utilized in spraying solder, to Which'it is'especially applicable. However, this is merely illustrative and is not to be construed in any sense as a limitation of the'- scope ofV utility of my invention, since it may be equally advantageously used in operating With other molten alloys and metals, not only in eii'ecting resurfacing operations, but in building up surfaces and creating designs in intaglio and relief.

As is Well known, solder is employed in filling and building up indented metallic surfaces to permit of theirrrestoration to their original unmarredY appearance, as in removing collision marks in'motor vehicle bodies, fenders and the like. The solder isapplied either by hand iny the conventional Way, -or by spraying it from a gun. The hand method is not only a laborious and costly operation but can only be satisfacl torily performed by skilled artisans While'the gun spraying process was evolved to reduce the high costs and obviate other disadvantages of the Vhand methods, the apparatus available for doing the'work do not possess those characteristics which ithas been found, are essential to its performance in an efficient and economical manner, as is requisite for commercial purposes. For instance, as pointed out in my co-pending application for LettersPatent, Serial No. 130,475, filed' March `12,' 1937, of which this application isa continuation in part, prior to my invention, it was necessary for the operator to employ both hands inthe use of thespraying apparatus, the gun being held in one, while the solder stick was supported Vinl the melting |chamber of the apparatus by the other. This, obviously, is awkward for the operator, with the result that he frequently relaxes his hold on the solder stick, which either drops out of thegun or tilts at an angle therein to admit air to the melting chamber, causing the solderto solidify and producing an interruption in theiwork while the chamber is cleared ofthe accumulation, with a consequent "Waste of time and material.` Further, because' of the manner in which th@ Solder is Vfed to the melting chamberandv the ineiiiciency in the functioning of the air nozzle, 4incomplete atomization frequently results and the solder fails to adhere to the surface under treatment or *forms a sol-called blotch thereon, which must be removed before the Vv'Work may proceed; also, the operator is unable to accurately direct the molten alloy spray when the' conditions `-of use make it necessary to hold the gun at certain angles to thevertical, entailing'extra labor' and expense in Ithe removal 'of the surplus deposit, aside fromthe Waste of time and material. i

While the invention of my aforesaidV application overcomes many of the dsadvantagesof apparatus available prior thereto, I have recognized that'in order' to obtain greater veiiciei'icy and economy in the practicing of metalv spraying processes generallyE and especially` as employed in the restoration of indented surfaces to their original contour, higher operating temperatures and faster initial heating of rthe apparatus,-Were essential, together with lower operating-costs' and a'greater range' of adaptability to the requirements of unskilled labor. l

Therefore, the primary object of thisiriventionl is to provide a morepraotical, highly vefficientV and economicalVv 'methodv and means of spraying molten'solder or leald, than is now-'existent, as utilizedv in 'the building up of metallic surfaces generally, as well as other molten metals or metallic alloys, for whatever purposes they be desiredY or applied.'

It is a further objectof this invention to provide a metal spraying'apparatus' of a simple and durable construction, by means of which a piece of work may be executed by the unskilled, without Waste of material and with'the facility and precision that is dinicult of attainment by skilled artisans, using existing types 'of apparatus.

More specifically, it is the object of this invention to provide a vmetal spraying apparatus or gun, whichA will heat faster initially andoperate at higher temperatures than any prior'apparatus, thereby reducing the time 'necessary to institute operations and materially increasing the efficiency by obtaining ya more4 complete atomization of the metal being sprayed, than is now possible, with a concomitant elimination of clogging of the melting chamber andthe resultant interruption of the work.

Another object of this invention is* tov provide av met-al spraying apparatushavingI the aforesaid characteristics, in which the heat'is'ge'nerated and concentiiated in the zone of: the chamber rin Which. the metal Vis melted, which4 is isothe direction or placement of the spray may be accurately controlled b-y the operator, irrespective of the angle at which the apparatus may be held relatively to the work, the nozzle `also contributing materially to improved atomizaltion of the molten metal.

A further and important object of this invention is the 'elimination of possible so-called blotching which occurs in the use of the gun, when the emission'ofY air from the nozzle is noncontinuous or intermittent, my apparatus including an aircontrol systeminV which means are incorporated for insuring a continuous emission of air from the nozzle while thegun is held in operating position in the hand.

Another object of my invention is to facilitate execution of the work by providing means for supporting theV solder stick in the melting chamber of the apparatus so that the latter may be conveniently'manipulated with one hand, this supporting vmeans insuring a positive and continuous feeding of the solder-to the chamber outlet and eliminating premature chilling and solidification of the solder within the chamber, which occurs in the use of prior apparatus as heretofore'pointed out.

Further important objectives of my invention are to increase the factor of safety in the use of spraying apparatus, add Ito its sphere of utility and provide for the ready conversion of the gun for operating with metals and alloys of various melting points.

Other objects 'and advantages flowing from the practicing of my invention will become manifest as the description' proceeds, and I would have it understood that IV reserve untomyself all rights to the full range of equivalents, both in structure and in avenues of use, to which I may be entitled under my invention in its broadest aspect.

In the accompanying drawings, I have shown a preferred embodiment `of my invention. However, it may take other forms to meet requirements of production and use and in attaining the objectives .to which it is directed, within the pur- View of the appended claims.

In the drawings:

Figure 1 is a side elevation of a spraying apparatus conforming to my Invention.

Figure 2 is a 'front elevation of the structure of the preceding figure.

Figure 3 is a sectional elevation of the apparatus. Y

'Figure 4 is a longitudinal section of the barrel on the line 4 4 of lFigure 3.

Figure 5 is a bottom plan View of the forward portion of the barrel of the apparatus.

Figure 6 is a perspective of the air nozzle of the apparatus, and

Figure 7 is a view in perspective of the heating unit located at the head end of the barrel.

Referring now to the `drawings in detail, in which like characters of reference are' employed to designate similar parts in the several views, 'I indicates the body or barrel of the apparatus or so-called spray gun which may be cast of aluminum or other suitable metal, in the cong'uration, and embodies a peripheral flange 8 and associated circumferential ribs 9 adjacent its larger end, the flange serving as a mounting for the components of the head assembly. This assembly includes a pair of annular plates I0 and I I, preferably of ferrous metal, between which is interposed the heating unit I2, the plate I0 being ribbed, as at IIIa and apertured to receive the screws I3 which pass through the openings I4 in the heating unit for threaded engagement with complemental holes in the under plate Il,

.the interconnected plates being secured to said flange -8 in spaced relation to the end of the barrel by the screws 8a and the cooperating ribbed sleeves 8b.

As will be observed, the head plate I0 is formed, as at I4, to provide a so-called melting chamber Ida of a conical shape which, at its upper end, merges into a cylindrical portion |40, preferably tapped -to receive the complementally threaded tube I5. This tube is adapted to function as a support and guide for a stick of solder or 4the like inserted in the melting chamber, making it unnecessary for the operator to hold the stick in the chamber, as in prior devices. Also, by thus supporting the stick, contact between thelower end thereof and the surrounding wall of the melting chamber is continuously maintained, 1rrespective of the angle at which the gun may be held in use, so that air cannot pass by the stick to the lower end of the chamber and prematurely chill the molten metal and cause clogging of the outlet. The lower end of the chamber Ila, merges int-o a small diameter cylindrical passage IlIb, opening to the atmosphere at Idd, in proximity to the outlet of the air nozzle I6.

The aforesaid air nozzle is of a block-like form, the head end thereof being composed of oppositely disposed chamfered surfaces I6a and ISb, with the discharge outlet I'I, which is an arcuate slot-like orifice, located in the lower angularly disposed surface |61), .the outlet com- .municating with the nozzle bore I8 in which one end of the air supply tubing IS is entered. The nozzle is mounted on the plate I 0, which embodies a pair of integrally formed lugs Ia, between which the nozzle-forming block is positioned and to which it is pinned or otherwise secured, the nozzle outlet being below the plane of the melting chamber outlet I4d and on a line inclined downwardly at an angle of approximately 45 to the longitudinal axis of the mel-ting chamber.

The melting chamber, while preferably integral with the plate I0, as shown, may be separately formed and xed thereto by any suitable means; also, the plates I0 and II may take other shapes 'and other methods may be utilized for connecting the head assembly to the barrel 1. Also, in the formation of the nozzle outlet IT, 'any practical method may be followed, in the present showing, the upper inclined surface Ilia of the head-end of Ithe nozzle block being undercut to form the base of the arcuate orifice, a plate I6c appropriately lconformed to define the top of the lunate orifice being associated with `the surface I 6a and welded thereto.

A so-called composite stock or grip includes an upper all-metal section 23, which embodies a flange 23a and a lower section 33 formed of wood or'other non-metallic material, embodying laterallyprojecting surfaces or shoulders 33a, the extensions 33h of sai-d lower section above said shoulders being entered in the lower slotted-end lof the upper stock section and t-he two sections interlockingly connected by the boltv 34 countersunk in the base of the lower section and threaded into that of th@ upper one, as clearly shown in Figure 3. Suitable facing plates 35, of metal, formed to meet and lie flush with said shoulders 33a, are superimposed upon the sides of the nonmetallic section of the stock and secured thereto by screws or the like.

As will be apparent, the flange 23al of the upper section 23 of the stock is apertured for the reception of the screws 24 which are adapted to be threaded into the base of the shouldered portion 'Ic of the barrel 'I for connecting the stock assembly thereto, the latter being spaced from the barrel by the interposed ribbed sleeves 25 embracing said screws. This spacing of the stock from the barrel and the composite construction of the stock insures convenient handling of the apparatus and efficient operation, since the handle or stock remains cool under constant useirrespective of the temperatures Aat which the gun may be functioning.

It will be noted that the aforesaid tube I9, connected to the nozzle I6, enters the barrel 1 through the slot 'lb and is coupled to the nipple 20 threaded into the top of the stock section 23. in communication with the vertical passage 2l which, in turn, communicates with the horizontal passage 22, also in said stock section 23. At one end, this passage 22 communicates with the tting 2S which embodies a valve chamber formed f with a valve seat 21 to receive the ball valve 2B, conned within said chamber, the outer end of said fitting being connectable to an air line leading from a tank, compressor or other source o-f supply. At its other end, the passage 22,

which extends across the stock, is ared outwardly, as at 22a, to form a seat for `the cmplemental surface of the head 29 of the rod 30, which is freely movable longitudinally of the passage, for controlling the seating and unseating of the valve 28.

A lever or trigger 3|, pivotally mounted on the stock, as at 32, is formed to abut upon the head 29 of the rod 30, the manual actuation of the trigger toward the stock being effective to urge the rod inwardly to impinge against and unseat the valve 28 in opposition to the counter air pressure, to permit the air to flow past the valve and into the communicating passages for emission from the nozzle orifice I1, it being evident that as the valve is unseated, the inner end of the rod head will cooperate with the complemental surface 22a, at the end of the bore 22, to seal this extremity of the passage and prevent the exhaust of air except from the lunate orice of the nozzle. When the pressure effective upon the trigger to open the valve is released, as at the conclusion of an operation, the valve 28 is instantly seated in response to the impinging air stream entering the fitting 26, it being obvious that the rod 3U is simultaneously urged outwardly with a concurrent rocking f the lever upon which the rod head abuts. Suitable stops are provided to limit the movement of the lever or trigger 3l in each direction, the o-iset upper end Sla thereof, being adapted to engage a lug 23h on the head of the stock section 23 to limit the movement of the trigger outwardly, while the pin 36 adjacent the lower end of the trigger, which is entered in a sleeve 31 countersunk in the stock section 33, limits the movement of the trigger in the reverse direction.

By mounting the lever or trigger as described and making it of a length approximating that of the stock, it will be evident that when the stock is grasped in the hand o-f the operatorl of the gun, the trigger must of necessity be actuatedV to open the valve for emission of air from the nozzle I6, the air being continuously emitted while the gun is being held in functioning position. Thus, constant emission of `air from the nozzle and continuous atomization of the molten metal issuing from the melting chamber outlet is assured during the use of the gun, any possibility of so-called blotching, 4because of relaxation of pressure on the trigger, as may happen in the use of prior devices, being entirely eliminated.

The heating unit l2, mounted between the plates l0 and Il, may be of 'any standard construction, embodying the usual mica plates I2a between which the electrical element is located, the leads 40 and 4i of the latter being connected to a source of electrical energy through the medium of the two-wire cable 43, provided with the usual appliance plug 44. 'Ihis cable enters the barrel 1 through an insulating bushing or collar 42, threaded into the rear end of the barrel, the respective wires being joined to the aforesaid element leads by the connectors 45 and 46 to which the wires are secured by the usual screws. To eliminate any possibility of shortcircuiting within the barrel, the element leads are embraced by a series of insulating blocks or collars 41 'and 43, between the unit and the aforesaid connectors, the wires and the cable being covered with a conforming plastic 'or pliable insulating material, which takes the form of a Y, the stem 49a of which is greater in diameter than the barrel opening through which the cable enters and is embraced by ya collar 50. As will be apparent, the enlarged stem of the Y-shaped insulating material, together with the associated collar 50, prevents movement of the cable within the barrel in response to any pull which may be exerted thereon externally of said barrel, which, otherwise, might break the circuit at the connectors or elsewhere Within the barrel, thereby not -only increasing the factor of safety in the use of the apparatus, but adding to its durability.

From the structure described, it will be evident that I have provided a gun of an entirely practical design which will function at the high temperatures which it has long been. recognized are essential to complete atomization and efiicient and economical performance, but which were unattainable in the use of prior apparatus, because of their construction and the limitations imposed thereby in the use of the heating unit or element. All previous types of spraying apparatus have -been of 'a unitary design, the heating element being incorporated in the barrel, with the melting chamber relatively so disposed that the heat losses were considerable. In fact, instead of the heat being concentrated in the area of the melting chamber,4 it was transmitted through the entire apparatus, the stock, in many instances, becoming heated to a degree that interfered with the handling of the gun. For this reason, and because of the fact that the apparatus were cast of aluminum to facilitate their handling, the critical point of which is 1200" F. it was necessary to limit the maximum temperature to approximately 650 F., in some cases a thermostat being employed for the purpose. This has resulted in slowv initial heating and inefficient performance, the relativelyV low temperature at which the molten metal issues from the melting chamber dropping to a point, under the influence of the impinging cold air stream, which results in poor characteristics, the loose sandy-like mass lacking the essential adhesive properties.

With my apparatus, the head assembly, insulated from the remainder of the structure, and formed of ferrous metal, permits of the use of a heating element whereby operating temperatures in excess of 1000 F. may be safely employed, and without the slightest inconvenience to the operator or the possibility of detrimentally affecting the aluminum barrel or the metal of the stock. Furthermore, in my construction, the heat is concentrated at that point Where it is requiredthe melting chamber, the heat being transferred from the heating unit to the entire surrounding walLof the chamber to eifect a more uniform melting of the metal supported therein7 than is obtainable in prior devices.

A practical commercial gun conforming to my invention heats initially to a temperature of 1400u F, within a few minutes and an average operating temperature of approximately 1000 F. is maintained at all times While spraying. This high temperature lquenes the solder more uniformly, for the reason above pointed out, and a ner and hotter spray is obtained which, of course, adheres to the surface under treatment more uniformly and compactly than the spray that is produced by the existing low temperature apparatus. Another advantage of my construction is its adaptability to use with low grade f solders or lead, whereas, with the low temperature apparatus a special solder is required. Of course, it may also successfully operate with other metals, having a higher melting point than solder, the requisite temperature being attained by the use of a heating element of the wattage necessary to produce it, which may be readily interposed between the head plates in the manner described, the gun being used in the ordinary manner.

While I have described my invention more or less specifically with reference to a specic form of use, as heretofore pointed'out, it may be applied to other uses with equal advantages, economically and otherwise, it bemg obvious that the head assembly may take such forms as may be required for different types of metals and that the heating element may be of different electrical characteristics; also the barrel and stock may be otherwise constructed,'while the form of valve mechanism for controlling the air stream may be varied to meet production or other requirements, in attaining the objectives of my invention as heretofore set forth and Without departing from the spirit and scope thereof, as set forth in the following claims.

I claim:

1. A head assembly for a hand-operated metal spraying apparatus, including a pair of annular metal plates, a metal melting chamber, embodying an outlet formed integral with one of said plates, the outer -surfacefof said plate being provided with cooling ribs, a heating unit interposed between said plates andan air nozzle carried by one of said plates, said nozzle having its outlet bel-ow and to the rear of the outlet from said melting chamber.

2. A head assembly for a hand-operated metal spraying apparatus, including a pair of annular metal plates, a metal melting chamber formed integral with one of said plates, said chamber having an outlet at its base, a heating unit interposed between said plates and an air nozzle carried by one of said plates, said nozzle having a lunate outlet for emitting air to propel the molten metal issuing from said chamber toward the work, said nozzle outlet being below and to the rear of the melting chamber outlet.

MORRIS M. SAVEDOFF. 

